It's that time of the evening. Everyone's eaten, all your shows have gone off, and the kids are in bed...so what now? You brush your teeth and migrate back to your own bedroom. Maybe you put on some background tv or even hop on the phone to see what everyone did that day. After a half hour or so, you finally get tired of social media/funny cat videos and decide to pass out. Six or seven hours later, it's time to wake up and you slap the snooze button--AGAIN! Why don't you EVER feel refreshed when you wake up? After 7 hours of sleep, you'd think your body would be ready to roll; but it never is. It seems we have forgotten how important LIGHT is to our health; so let's refresh your memory AND your sleep by addressing some fundamentals.
Humans are DIURNAL Mammals
"Diurnal" is a term meaning "of or during the day". It is used to describe living organisms that are adapted to perform MOST of their functions during the day, rather than at night like "nocturnal" organisms that are more active at night. So how do we know this? Unlike nocturnal species that have more rods in their retinas, diurnal species cannot differentiate movement in low light environments very effectively. Instead, diurnal animals tend to have higher concentrations of cones in the retina (like US) that are responsible for color vision in daylight activities.
Humans typically have trichromatic vision, meaning that we normally have three specialized types of cone cells (S-Cones, M-Cones and L-Cones) which recognize three distinct color wavelengths (short, medium and long). This is important to know because the light we get from the sun and our electronics emit varying wavelengths of light that we are adapted to respond to. This might all sound nerdy, but it is important to know because the interplay between these cones and your environment are what's keeping you from sleeping well!
The Physiology of Wake/Sleep Cycles
You probably remember your science teacher explaining "Red and Blue Shift" phenomena, and how we see certain stars as more red or blue based on how far away they are, right? Well, that seemingly unimportant tidbit of information actually matters in your health. As the Earth rotates toward the sun every morning, the S-Cones pick up on something that otherwise isn't there. The blue shift of a sunrise coming in our window (due to us moving ever so slightly towards the sun) stimulates these cones to release cortisol. This is because our brains perceive the faster moving waves of light as a stimulus that we need to be ready for. Cortisol gets a bad rap as the "stress hormone", but really it's primary function is to jumpstart our brains and energy systems in the morning before we eat. In healthy people, this response happens at first light (even coming in a window across the room); but overexposure to high frequency lighting (fluorescent bulbs and electronics) actually throws these processes out of balance.
Conversely, sunsets have the opposite effect. When the Earth is again in alignment with the sun (but moving away from it), we perceive a "red" shift. This activates the L-Cones of our eyes, signaling the brain to release our relaxation/recovery hormones. The slowing down of light, therefore, is the trigger by which our brains recognize that it is safe to recover; and it begins this process by releasing melatonin. Melatonin is our body's most powerful antioxidant, and is the hormone responsible for balancing our other hormones and regenerating tissues while we sleep. Ever wonder why campfires and fireplaces are so relaxing? It's because your L-Cones have hours of low-level red light stimulation to pump you full of melatonin in preparation for a good night's sleep and recovery.
Where Have We Gone Wrong?
Since the days of World War II and "Rosie the Riveter", industrialized nations have been working longer and longer days compared to pre-industrialized societies. We get up long before the sunrise, are inside under fluorescent lights 9+ hours a day, get home after sunset, and/or work irregular shifts (2nd/3rd shift, etc) separating us from the daylight cycles we should be synced with. Not only that, but our leisure activities are becoming more and more digital, which expose us to higher and higher amounts of synthetic sunlight people are only recently becoming aware of. Rather than having a gradual increase of blue light that just as gradually transitions into red light for an optimal hormone cycle, we have chosen to go from darkness to artificial light and back to darkness on a daily basis. You should think of this like going to the gym for the first time and someone putting 300 lbs. on the bench, then making you struggle to no avail, then sending you home to repeat this every day as your training plan. The body couldn't adapt to this kind of program because ADAPTATION requires PROGRESSION, so we can't expect our hormonal cycles to work properly in such erratic conditions.
How Do We Correct This?
Easy...we NORMALIZE our blue-to-red light progressions of light exposure! Consider that every time you look at a screen, the focused blue light surrounded by darkness is basically telling your brain "that's a sun, so wake up" by releasing cortisol. This prematurely kickstarts your systems as if you were needing to get up in the morning. It is also why, after a night of watching TV or being on other electronics, it takes longer to fall asleep and stay asleep than it should. Therefore, using electronics when you should be winding down is like hormonally waking up a second time in your day...no wonder your body gets tired!
You can remedy this by creating an evening routine that mimics that of sitting by a campfire for a couple of hours before bed. Remove watching television or playing on your phone/electronics during the two hours prior to bedtime; so that your brain is not exposed to the blue light they produce. Instead, use that time to socialize/bond with your loved ones (board games, homework, story time) or center yourself (meditation, paper journaling, book reading, etc.) under softer light conditions. Utilize indirect lighting from bulbs 60W or lower to keep these evening activities much more like sunset conditions so that the L-Cones in your eyes recognize its time to relax. Controlling your lighting environment in this way triggers your brain to release melatonin like it should, rather than stimulating cortisol like high frequency light exposure would otherwise.
Telling stories in indirect low light is a great way to reduce blue light exposure and bond with loved ones!
For some people, avoiding blue light from electronics during the evening hours is unavoidable due to work requirements/other factors. With these people, I recommend activating the blue light filter functions of their electronics (normally this can be found in the device's settings). These filters will usually prompt you for when you want them to run, so you should set them to "sunset to sunrise". You'll also want to set their opacity to as warm as possible, to turn down blue light emissions further than the standard settings. Another hack to consider would be purchasing blue light filtering glasses like those offered by Gunnar or other similar brands. Even though neither of these tweaks remove ALL blue light from your perception, they diminish it enough that you should fall asleep and stay asleep easier than you have become accustomed.
Next, removing unnecessary light sources from your bedroom will further decrease your evening/night blue light exposure. Take the TV/internet modem/etc out of there...plug your phone in elsewhere...use an older mechanical alarm clock or one with only red lights ideally. Even the smallest LED lights can be triggers for the mechanisms mentioned above, so getting them out of your sleeping space should be a priority when wanting to optimize your sleeping patterns. If it isn't possible or practical to do these things, then cover the lights of these objects with black electrical tape so that their light is blocked from interrupting your ideal sleep cycles. For my shift workers out there, cover your bedroom windows with blackout curtains and seal the edges so daylight doesn't disrupt your sleep cycle.
Example of an alarm clock without blue light emissions
Lastly, waking up slightly before sunrise should be a goal. This will align your morning routine with the natural blue light of the morning hours as the sun rises every morning. For those whose schedules prevent them from doing this, you should aim for two hours of sunlight or other bright light reaching your eyes at the start of your day. This might be by opening your office curtains, not wearing sunglasses when you leave the house, etc. Allowing natural blue light from the sun to wake your body up at the beginning of your day is optimal, but those on the night crew will want to use bright light exposure to mimic the sun in its absence.
A walk to start your day and get your blood flowing is another option for people stuck in an office all day. It gets you more sun exposure (morning crew), circulates nutrition to decrease cortisol demand, and is a properly timed way to increase your steps regardless of your situation!
What Have We Learned?
An appropriate two hour morning routine increasing natural blue light exposure, with a naturally lit work environment during the day, and a red-shifted evening ritual will greatly improve your body's natural hormone signaling. By designing your day according to these guidelines, most of you will be able to drastically improve your quality of sleep by re-aligning yourself with the daily sun patterns that we have been adapted to follow. Those of you that aren't able to implement the optimal lifestyle changes (due to work schedules) can still improve your health by implementing the hacks mentioned for you!
Since we need to get approximately 7-9 hours of QUALITY sleep per night in order for our bodies to work optimally, you shouldn't take these recommendations lightly. Avoid skipping a proper wind-down routine (such as listed above) because it will only hold you back from recovering fully. Otherwise, your brain doesn't know it is time to shut down until your eyes close; so the first hours of your sleep end up wasted, as your melatonin levels try to catch up! Instead, implement these changes to make more of those of sleep hours count, and leave you feeling more refreshed in the morning...like you SHOULD be.
I hope you've learned how you can better take control of your daily schedule with this article, and look forward to teaching you even more in those to come!